24 
preferable. The resin wash acts by contact, having ‘a certain caustic 
effect, but principally by forming an impervious, smothering coating 
over the scale insects. The application may be more liberal than with 
the kerosene washes, the object being to wet the bark thoroughly. 
The wash may be made as follows: 
Resin 2h Se LS ot Be A EG EE I pounds__ 20 
Crude caustic soda.(78 per, cent) 2225" ee ee dorian 
ESESh Ollie! 22 bp ohne thiel, ihe ee deo, A aE DINGS = alas 
Watery to make 320.20 yee eR 2 ee ee ee gallons__ 100 
Ordinary commercial resin is used, and the caustic soda is that put 
up for soap establishments, in large 200-pound drums. Smaller 
quantities may be obtained at soap factories, or the granulated caustic 
soda (98 per cent) may be used—3%$ pounds of the latter being the 
equivalent of 5 pounds of the crude. Place these substances, with 
the oil, in a kettle with water to cover them to a depth of 3 or 4 
inches. Boil about two hours, making occasional additions of water, 
or until the compound resembles very strong black coffee. Dilute to 
one-third the final bulk with hot water, or with cold water added 
slowly over the fire, making a stock mixture, to be diluted to the full 
amount as used. When sprayed the mixture should be perfectly 
fluid, without sediment, and should any appear in the stock mixture 
reheating should be resorted to; in fact the wash is preferably applied 
hot. 
As a winter wash for scale insects, and particularly for the more 
resistant San Jose scale (Aspidiotus perniciosus) , stronger washes are 
necessary. In southern California, for this insect, a dilution one- 
third less, or water to make 66% gallons instead of 100 (see for- 
mula), has given good results. In Maryland, with this insect, it has 
proved necessary to use the wash at six times the summer streneth 
to destroy all of the well-protected hibernating scales; and with 
other scale insects much stronger mixtures than those used in Cali- 
fornia have proved ineffectual in the East. For regions, therefore, 
with moderately severe winters the use of the resin wash to destroy 
hibernating scale insects seems inadvisable. 
THE LIME-SULPHUR WASH. 
In California, where the San Jose scale first appeared, the standard 
remedy for it is the lime-sulphur-salt wash, a mixture formerly used 
as a sheep dip in Australia and employed with little change against 
the San Jose scale. This wash was naturally first thought of on the 
discovery of the San Jose scale in eastern orchards. The earlier tests, 
however, conducted by this office in 1894, gave unfavorable results, | 
and the experimentation which followed resulted in the -demonstra- 
tion of several distinct and valuable methods of control noted below. 
127 

